Use of Functional Magnetic Resonance Imaging To Prove that A Witness is Not Lyiing Not Admitted Into Evidence

The 6th Circuit Court of Appeals has ruled that functional magnetic resonance imaging cannot be used in a criminal case to prove that the defendant’s denials of wrongdoing were true.

Defendant wanted to introduce evidence of the fMRI to prove that he was telling the truth in his criminal trial and that did not intentionally violate the law.  In an issue of first impression, the court of appeals affirmed the exclusion of the evidence.  The court said

that the district court did not abuse its discretion in excluding the fMRI evidence pursuant to Rule 403 in light of (1) the questions surrounding the reliability of fMRI lie detection tests in general and as performed on [defendant] Dr. Semrau, (2) the failure to give the prosecution an opportunity to participate in the testing, and (3) the test result’s inability to corroborate Dr. Semrau’s answers as to the particular offenses for which he was charged.

The prospect of introducing fMRI lie detection results into criminal trials is undoubtedly intriguing and, perhaps, a little scary.   See  Daniel S. Goldberg,  Against Reductionism in Law & Neuroscience, 11 Hous. J. Health L. & Pol’y 321, 324 n.6 (2012) (reviewing literature that “challenges the very idea that fMRI or other novel neuroimaging techniques either can or should be used as evidence in criminal proceedings.”).  There may well come a time when the capabilities, reliability, and acceptance of fMRI lie detection—or even a technology not yet envisioned—advances to the point that a trial judge will conclude, as did Dr. Laken in this case:  “I would subject myself to this over a jury any day.”  Though we are not at that point today, we recognize that as science moves forward the balancing of Rule 403 may well lean toward finding that the probative value for some advancing technology is sufficient.